Looking for a solution to water noise problem

Whenever any faucet is open in the house there is noise of rushing water in the basement pipes. The noise seems to be predominant at the PRV and at the pipe just above it, but the sound of water can also be heard throughout the rest of the pipes. Could the PRV be causing this noise or are there other factors involved? The PRV appears to be in good shape but it came with the house so it is 15+ years old. I did remove and clean the PRV strainer recently but that did not help. The strainer actually was fairly clean. Any advice would be appreciated.